Conventionally, a laminated core for a stepping motor has a very small air gap between a rotor core and a stator core. Thus, scrap pieces between a rotor core sheet and a stator core sheet have narrow widths. The scrap pieces may be broken during a punching operation and not drop downwardly into a die of a die device. In such a case, the punching operation has to be repeated. In addition, the die device may be damaged due to clogging of the scrap pieces. Furthermore, if outside teeth of the rotor core sheet and inside small teeth of the stator core sheet cannot be blanked from one strip material in desired shapes, the rotor core sheet and the stator core sheet need to be blanked separately with different die devices, which results in a low material yield and a high cost.
To solve the above problems, for example, Patent Document 1 discloses conventional art capable of blanking the rotor core sheet and the stator core sheet from one strip material with one die device by providing a thin section in at least one of the rotor core sheet and the stator core sheet. The thin section is formed by coining and flattening a surface of the rotor (or stator) core sheet in a thickness direction.